fix unlock error

iOSClient/Networking/NCNetworkingSync.m

@@ -243,7 +243,8 @@
             // LOCK
             [communication lockEndToEndFolderEncrypted:[url stringByAppendingString:@"/"] fileID:fileID token:tokenDatabase onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *token, NSString *redirectedServer) {
         
-                [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
+                if (token.length > 0)
+                    [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
             
                 // REMOVE METADATA
                 [communication deleteEndToEndMetadata:[url stringByAppendingString:@"/"] fileID:fileID onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *redirectedServer) {
@@ -323,7 +324,8 @@
             // LOCK
             [communication lockEndToEndFolderEncrypted:[url stringByAppendingString:@"/"] fileID:fileID token:tokenDatabase onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *token, NSString *redirectedServer) {
         
-                [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
+                if (token.length > 0)
+                    [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
             
                 // DELETE METADATA
                 [communication deleteEndToEndMetadata:[url stringByAppendingString:@"/"] fileID:fileID onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *redirectedServer) {
@@ -423,7 +425,8 @@
         // LOCK
         [communication lockEndToEndFolderEncrypted:[url stringByAppendingString:@"/"] fileID:fileID token:tokenDatabase onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *token, NSString *redirectedServer) {
             
-            [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
+            if (token.length > 0)
+                [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
             
             // DELETE METADATA
             [communication deleteEndToEndMetadata:[url stringByAppendingString:@"/"] fileID:fileID onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *redirectedServer) {
@@ -486,7 +489,8 @@
         // LOCK
         [communication lockEndToEndFolderEncrypted:[url stringByAppendingString:@"/"] fileID:fileID token:tokenDatabase onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *token, NSString *redirectedServer) {
         
-            [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
+            if (token.length > 0)
+                [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
         
             // STORE METADATA
             [communication storeEndToEndMetadata:[url stringByAppendingString:@"/"] fileID:fileID encryptedMetadata:metadata onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *encryptedMetadata, NSString *redirectedServer) {
@@ -549,7 +553,8 @@
         // LOCK
         [communication lockEndToEndFolderEncrypted:[url stringByAppendingString:@"/"] fileID:fileID token:tokenDatabase onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *token, NSString *redirectedServer) {
         
-            [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
+            if (token.length > 0)
+                [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
         
             // UPDATA METADATA
             [communication updateEndToEndMetadata:[url stringByAppendingString:@"/"] fileID:fileID encryptedMetadata:metadata token:token onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *encryptedMetadata, NSString *redirectedServer) {
@@ -613,7 +618,8 @@
         [communication lockEndToEndFolderEncrypted:[url stringByAppendingString:@"/"] fileID:fileID token:tokenDatabase onCommunication:communication successRequest:^(NSHTTPURLResponse *response, NSString *token, NSString *redirectedServer) {
         
             // Write DB token
-            [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
+            if (token.length > 0)
+                [[NCManageDatabase sharedInstance] setDirectoryE2ETokenLockWithServerUrl:serverUrl token:token];
             dispatch_semaphore_signal(semaphore);
         
         } failureRequest:^(NSHTTPURLResponse *response, NSError *error, NSString *redirectedServer) {